A soldier participates in a tactile belt experiment. Vibrations on the belt can direct a soldier's movements without the platoon leader having to say a word. (Connie Fore / via Army)

Soldiers may develop a sixth sense for combat, but the Army’s not done working on the other five.

Case in point: Research on a belt that incorporates “vibrotactile” technology — nodes that surround the wearer’s body, buzzing in response to a GPS marker, a squad leader making hand signals while wearing a tricked-out glove, even a robot.

Feel a buzz on your stomach? Go straight. Tremor on your back? Turn around. A custom signal, like all the nodes firing at once? Maybe it’s time to get to the rally point. Or just get down.

“Normally, we navigate visually,” said Bruce Mortimer, director of research and development at Engineering Acoustics Inc., one of the companies attached to the Army Research Laboratory’s Tactile Multisensory Navigation and Communication Systems program. “We have to look at a map or a GPS display, figure out our orientation, do the mapping and orientation cognitively — it requires a lot of brainpower.”

Vibrotactile gear changes the pathway, bringing the information into the soldier’s brain, trading visual cues for a vibration similar to a silenced smartphone. It also allows soldiers to focus their other senses on incoming threats and, studies show, gives them higher confidence levels that they can recover their bearings when they take detours from a planned route.

In a recent ARL trial at Fort Benning, Georgia, groups of soldiers covered a 300-yard portion of a test course. Those who wore the belt made it through faster, but they also checked their navigation aides 1.2 times during the trek. Soldiers without the belt checked more than 17 times, on average.

“The tactile belt, in the navigation role, allows the soldier to not have to think about navigating,” Rodger Pettitt, a human factors specialist at ARL’s Benning-based human research and engineering directorate, said in a June 11 interview. “The benefit of that is, it allows the soldier to keep his eyes on the terrain, without having to look at an instrument or a GPS. Always, in his mind, he knows where his waypoint or objective is.”

Or, as one soldier put it after a test, the gear is “hands-free, eyes-free, and mind-free.”

Fits like a glove

Tactile-based communications research has been going on for a half-century, Mortimer said, beginning with studies using the vibrations to engage the blind or deaf. Other military-related applications include trial programs treating service members with inner-ear injuries, often stemming from explosions: A vibration could warn them that they’re off balance, for instance.

Until recently, work has centered on the aviation industry, with Army researchers at Fort Rucker, Alabama, using the sensors as a way to tell helicopter pilots whether they’re landing level. A version even made it into the early rounds of the Joint Strike Fighter program, Mortimer said, though tactors — the fancy word for the belt-embedded buzzers — can have trouble cutting through G-forces and the other rumblings associated with a jet cockpit.

The ARL picked up the tactile-navigation angle around 2003, said Linda Elliott, an ARL research psychologist also at Fort Benning. Early tests “pretty much proved the concept, that this could be extremely useful,” she said. “It was very well received with the soldiers.”

EAI came onboard later, as did AnthroTronix, which provides what it calls the NuGlove: a device designed for small-unit leaders who can control the buzzes sent to their squadmates through traditional hand signals.

In addition to letting soldiers “feel” the signals at night or when obstacles block their view, the same glove could be used to direct a robot’s movements, AnthroTronix President Jack Vice said in an interview. And the robot could send signals back to soldiers via vibrations — noting a threat or marking a milestone, all without a visual or auditory cue for enemy forces.

That level of secrecy has intrigued at least some soldiers who’ve tested the gear, Elliott said.

“You can program your own signals, make up your own pattern,” she said. “Snipers, for example, liked the ability to have covert communications, because covertness is what they’re all about.”

On the horizon

The EAI belt underwent a successful navigation test in March, Elliott said, and the NuGlove performed well in its last outing in fall 2013. Future tests will continue tinkering with the types of signals soldiers can receive via the belts, but the next steps in fielding such gear involve factors beyond its performance in trials:

■Weight and power: The belt weighs about 0.8 pounds, Mortimer said, but Army officials consider the benefits of every ounce of gear. The tactors require minimal power, but their output might need to be boosted for soldiers on missions that would involve a good deal of tactile interference — rumbling tank treads or exceedingly rough terrain, for example.

The glove could be a standard-issue glove with a few sensors, taking up about the same amount of power as a computer mouse and able to connect to any available power source, Vice said.

■Combat readiness: The gear hasn’t cracked under testing, Pettitt said, but the trials don’t mimic all harsh combat conditions. The signal strength may need to be boosted to cover a small unit’s operating area, and it likely would need some form of encryption before fielding.

■Host system: Don’t expect a belt and a glove to show up at your unit’s doorstep — it’s likely the gear would be integrated into the Nett Warrior system or a similar “future soldier” setup, which would include a wearable battery that could be tapped by the belt and a smartphone-like device that could house the operating system for both belt and glove.

Vice said the NuGlove has received interest from the researchers behind the Tactical Assault Light Operator Suit — better known as TALOS, but also known as “the ‘Iron Man’ suit,” with official Defense Department releases comparing it to the comic-book gear.

“Once the soldier gets some kind of computer on board ... having these sensors that we integrate into the standard field glove is a no-brainer,” Vice said. “It’s not a matter of if it will happen, it’s a matter of when.”